This standard specifies the method for determining the 1% (m/m) sodium hydroxide extract content of papermaking raw materials. This standard is applicable to wood and non-wood fiber raw materials. GB/T 2677.5-1993 Determination of 1% sodium hydroxide extract content of papermaking raw materials GB/T2677.5-1993 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Determination of 1% sodium hydroxide soluhility in papermaking raw materials
Fibruus ra material-Determining of 0.1% sodium hydroxide soluhility
1 Subject content and applicable scope
This standard specifies the method for determining the 1% (m/m) sodium hydroxide extract content in papermaking raw materials. This standard is applicable to fiber raw materials of papermaking materials and non-papermaking materials. 2 Reference standards
GB601 Preparation method of chemical reagent standard solution GB603 Preparation method of chemical reagent preparation and product GB2677.1 Sampling of samples for papermaking raw material analysis GB 2677.2 Determination of moisture content of papermaking raw material
3 Principle
CB/T 2677. 5-93
Substitute G2677.581
The determination method is to treat the sample with 1% (m/m) sodium hydroxide, wash and dry it, and then determine the content of its extract. 4 Reagents
During analysis, analytical reagents must be used, and the test water should comply with the provisions of Article 4.1. 4.1 Distilled water or deionized water
4.2 Methyl orange indicator solution: 1g/L.
Weigh 0. 1 g of methyl orange and dissolve it in water, dilute to 100 ml. 4.3 Ammonia solution; 100 g/1.。
, weigh 11.7 g of barium chloride (BaCl · 2H,0) and dissolve it in 100 mL of water. 4.4 Phenolic acid indicator solution: 10 g/L.
Weigh 1.0 g of phenolic acid and dissolve it in 95% ethanol solution, and dilute it to 100 mL with ethanol. 4.5 Cresol chloride indicator solution: 1 g/L
Weigh 0.1 g of methyl bromide and dissolve it in 95% ethanol solution, and dilute it to 100 mL with ethanol. 4.6 Phenol red indicator solution: 2 g/L.
Weigh 2 g/L of methyl red and dissolve it in 95% ethanol solution, and dilute it to 100 mL with ethanol. 4.7 Cresol green-methyl red indicator solution.
Take 3 parts of 1/1.5 g/L cresol green ethanol solution and 1 part of 2 g/L methyl red ethanol solution, mix them, shake the spoon, 4.8 Standard hydrochloric acid titration solution: c(HC1)=0.1 mol/1. 4.8.1 Preparation: Measure 9 mL of concentrated hydrochloric acid (22st=1.J9 g/ml.), dilute with water to 11., take a sentence. Approved by the State Bureau of Technical Supervision on March 1, 1993 and implemented on October 1, 1993
GB/T 2677. 5-93
4+8.2 calibration, weigh 0.2g of standard anhydrous sodium carbonate burned to constant weight at 270~300℃, accurate to 0.00028, dissolve in 50m water, add 10 drops of bromocresol green-methyl red mixed indicator, titrate with 0.1 mol/L hydrochloric acid standard titration solution until the solution changes from green to dark red, boil for 2min, cool and continue titrating until the solution turns dark red. 4.8.3 Concentration calculation:
7V,-V,)X 0.052 99
Wherein: '—
Actual concentration of hydrochloric acid standard titration solution, mol/LThe mass of anhydrous sodium carbonate weighed during calibration, 9tG
V,——The volume of hydrochloric acid standard titration solution consumed during calibration + L1V, —The volume of hydrochloric acid standard titration solution consumed during blank test, mL! 0.052 99-
(1/2N2CO,>'s millimolar mass.
4. 9 Sodium hydroxide solution: 1% (m/m )
Dissolve 10g of sodium hydroxide in distilled water and transfer 1 4.9.11% (m/m) sodium hydroxide solution calibration method (1) (1)
Use a pipette to draw 50mL of sodium hydroxide into a 200mL volumetric flask, add 10mL of barium chloride solution (4.3>, then add water to dilute to the scale, shake, let it stand to allow the precipitate to drop, filter with dry filter paper and funnel, accurately draw 50mL of filtrate, add 1 to 2 drops of methyl orange indicator, titrate with 0.1mol/L hydrochloric acid standard titration solution, and calculate the concentration of the prepared sodium hydroxide solution cl (%) according to formula (2):
Where:
V*c× 40 × 100
1000×12.5
--Volume of standard hydrochloric acid solution consumed during titration, nL,-Concentration of standard hydrochloric acid solution, Iol/LI Volume of 1% (m/m) sodium hydroxide actually taken during titration, mL: molar mass of sodium hydroxide.
1000,100-
Conversion factor.
4.9.2 Standardization method of 1% (m/m) sodium hydroxide solution (2) (2)wwW.bzxz.Net
Weigh potassium hydrogen phthalate (KHCH40,0,>2g) that has been dried at 110°C to a constant mass, weigh to 0.0002g, dissolve in 80mL of boiled water, add 2-3 drops of phenolic acid indicator, and titrate directly with the prepared 1% (m/m) sodium hydroxide until red appears. Note the volume of 1% (m/m) sodium hydroxide consumed, and calculate its concentration c2 using formula (3). mX40×100
2(%) -
VX 204. 22
Wherein: me
the mass of potassium hydrogen phthalate weighed + name: the volume of 1% (m/m) sodium hydroxide consumed during titration, mls-the coulometric mass of potassium hydrogen phthalate;
40——the coulometric mass of sodium hydroxide;
100-the conversion factor.
(3)
If the concentration does not meet the requirements, a more concentrated alkali or water should be added to adjust the concentration to the required 0.9%-1.1% (equivalent to 0.25±0.025 mol/1.)
4.10 Acetic acid solution: 1:3 (V/V).
5 Instruments
5.1 General laboratory instruments.
5.2 Constant temperature water bath (adjustable from room temperature to 100℃). 5.3 30mL glass filter (1G2).
5.4 300mL conical flask.
5.5 Condenser.
5.6 Constant temperature oven.
6 Sample collection and preparation
GB/T 2677. 5-- 93
According to the provisions of GB2677.1, prepare an air-dried sample of not less than 20g + the sample is the part of the fine particles that can pass through the 40-mesh sieve but cannot pass through the 60-mesh sieve.
7 Test steps
Accurately weigh 1.9-2.1g (weighed to 0.0001g) of sample (simultaneously weigh another sample to determine the moisture content according to GB2677.2), put it into a clean 300mL conical flask, accurately add 100mL of 1% sodium hydroxide solution, install a reflux condenser or air condenser, heat in a boiling water bath for 1h, shake once each when heating for 10min, 25min, and 50min. After the specified time is reached, take out the conical flask, let it stand for a while to allow the residue to settle on the bottom of the flask, and then filter it through a 1G2 glass filter that has been constant weight by the pouring method. Wash the paint residue and the conical flask with warm water for several times, and finally wash all the residue in the conical flask into the filter, wash with water until there is no alkalinity, then wash the residue with 60ml acetic acid solution (4.10) two or three times, and finally wash with cold water until there is no acidic reaction (test with methyl orange indicator), suck off the filtrate, take out the stabilizer, wash the outside of the filter with distilled water, move it into the oven, and dry it at 105±2℃ until the mass is constant. 8 Result calculation
8.11% (m/m) oxygen oxidation extract must be measured twice at the same time, and the arithmetic mean is taken as the measurement result. The result is required to be rounded to one decimal place, and the deviation between the calculated values ​​of the two measurements should not exceed 0.4%. 1% (m/m) sodium hydroxide extract content, expressed as a percentage, is calculated according to formula (4): (%) = * = m × 100
Where:
absolute dry mass of the sample before extraction,
absolute dry mass of the sample after extraction.
9 Test report
The test report should include the following items:
National standard number:
Test data, location and reference materials
All information required for complete identification of the sample: d, operations not in accordance with the provisions of the standard and other factors that may affect the test results. Additional remarks:
This standard is proposed by the Ministry of Light Industry of the People's Republic of China. This standard is under the jurisdiction of the National Paper Industry Standardization Technical Committee. This standard is drafted by the Paper Industry Science Research Institute of the Ministry of Light Industry. This standard adopts the American standard TAPP1T2120m--88 "1% sodium hydroxide extract of wood and pulp". This standard was first published in 1961. The first revision was in 1981. (40
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